Gao Ze-Hua, Wei Kecheng, Wu Tao, Dong Jia, Jiang De-En, Sun Shouheng, Wang Lai-Sheng
Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
Department of Chemistry, University of California, Riverside, California 92521, United States.
J Am Chem Soc. 2022 Mar 30;144(12):5258-5262. doi: 10.1021/jacs.2c00725. Epub 2022 Mar 15.
It has been a long-standing challenge to create and identify the active sites of heterogeneous catalysts, because it is difficult to precisely control the interfacial chemistry at the molecular level. Here we report the synthesis and catalysis of a heteroleptic gold trihydride nanocluster, [AuH(dppe)(PPh)] [dppe = 1,2-bis(diphenylphosphino)ethane, PPh = triphenylphosphine]. The AuH core consists of two Au units bonded via six uncoordinated Au sites. The three H atoms bridge the six uncoordinated Au atoms and are found to play a key role in catalyzing electrochemical reduction of CO to CO with a 92.7% Faradaic efficiency (FE) at -0.6 V (vs RHE) and high reaction activity (134 A/g mass activity). The CO current density and FE remained nearly constant for the CO reduction reaction for more than 10 h, indicating remarkable stability of the AuH catalyst. The AuH catalytic performance is among the best Au-based catalysts reported thus far for electrochemical reduction of CO. Density functional theory (DFT) calculations suggest that the hydride coordinated Au sites are the active centers, which facilitate the formation of the key *COOH intermediate.
创建和识别多相催化剂的活性位点一直是一项长期挑战，因为在分子水平上精确控制界面化学很困难。在此，我们报道了一种杂配型三氢化金纳米团簇[AuH(dppe)(PPh)] [dppe = 1,2 - 双(二苯基膦基)乙烷，PPh = 三苯基膦]的合成与催化性能。AuH核由通过六个未配位的金位点相连的两个金单元组成。三个氢原子桥连六个未配位的金原子，并且发现在 -0.6 V（相对于可逆氢电极）下催化CO电化学还原为CO时，它们起着关键作用，法拉第效率（FE）为92.7%，反应活性高（质量活性为134 A/g）。在CO还原反应中，CO电流密度和FE在超过10小时内几乎保持恒定，表明AuH催化剂具有显著的稳定性。AuH的催化性能是迄今为止报道的用于CO电化学还原的最佳金基催化剂之一。密度泛函理论（DFT）计算表明，氢化物配位的金位点是活性中心，有助于关键的*COOH中间体的形成。
